Many kinds of board products have been made from woody plant fibers in the form of chips, slabs, strands, shreds, particles, sawdust, shavings, comminutions, and other fiber forms. Such fibrous materials have been bound together using a variety of binders and forming methods to produce boards or panels referred to as chipboard, particle board, fiberboard, strand board, wood-wool board, veneer board, and pressboard, to name just some.
It is known that the woody rinds of grasses such as sugarcane and sweet sorghum can be used in producing some of such boards. Additionally, it is known that such rinds, that is the fibers from such rinds, can be aligned and bonded to form boards having characteristics much like solid natural hardwood.
United States patents have been granted on various improvements relating to the above-noted manufactured panels and boards, including the following patents:
U.S. Pat. No. 2,592,470 (Ryberg) PA1 U.S. Pat. No. 2,648,262 (Croston et al.) PA1 U.S. Pat. No. 2,717,420 (Roy) PA1 U.S. Pat. No. 2,853,413 (Christian) PA1 U.S. Pat. No. 3,164,511 (Elmendorf) PA1 U.S. Pat. No. 3,464,881 (Miller et al.) PA1 U.S. Pat. No. 3,464,877 (Miller et al.) PA1 U.S. Pat. No. 3,567,511 (Tilby) PA1 U.S. Pat. No. 3,690,358 (Tilby) PA1 U.S. Pat. No. 4,025,278 (Tilby) PA1 U.S. Pat. No. 4,212,616 (Tilby) PA1 U.S. Pat. No. 4,312,677 (Tilby et al.).
While some of these patents relate to the solid boards mentioned above, most relate to lighter and less expensive boards and panels. A long-standing problem or shortcoming of the latter boards and panels is their structural weakness. Because of this, few of them have excellent weight-bearing and structural characteristics; such boards and panels often serve lesser covering, underlying, or decorative needs. Many of such boards and panels have little ability to serve in situations exposing them to weather, because weakening can occur.
In many cases, the strength of such panels and boards is provided primarily by the binder rather than by the fibers used in manufacture. In some cases, a degree of strength is achieved by the degree of packing. In others, the use of large amounts of binder per unit volume of product increases the cost of such panels.
Such panels not only are lacking in structural strength, but typically do not have good insulating qualities. Because of this the usefulness of such panels is often quite limited.
Manufacture of such panels and boards has been carried out in various methods, some requiring complex extrusion equipment or other manufacturing equipment. The processes used in making such panels and boards often require extended periods to achieve drying throughout the cross-section of the board or panel, and significant amounts of energy.
A major problem in many developing countries and elsewhere is the shortage of high-quality building materials or, stated differently, the high cost of materials used for various building needs, including residential housing. In many cases, locally manufactured materials may not be available, requiring importation which adds to costs.
In summary, there is a clear need for an improved apparatus and method for manufacture of structural panels. Such apparatus must be low in cost and be able to produce low-cost, light-weight structural panels having good load-bearing qualities, good insulative qualities, and good weather-resistance An apparatus for production of structural panels from sugarcane and sorghum rinds, particularly in developing countries, would provide important advantages.